Pavement.



W. B. WARREN.

Patented Mar.

. of Newton, in the county of Middlesex and I ence tothe drawings, in whichart or science to which; saidfinvention relates to make and use the same.

placed. thata lower-iportion-of each element w th the topping or wearing surface. The

WALTER BURGESS WARREN, a. NEWTON,

PATENT-OFFICE.

MASSACHUSETTS, ASSIGNOR TO WARREN BROTHERSCOMPNY, OF BOSTON MASSACHUSETTS, "A CORPORATION OF WEST VIRGINIA.

PAVEMENT.

Specification oflLetters ram. Patented March 23, 1909. Application filed June 22, 1903. Serial m5. ie2,51 7.

To all whom it may concern Be it known that I, WALTER B. WARREN,

State of Massachusetts, a citizen ofthe United States, have made certain new and useful Improvements Pavements, and-do hereby declare the following to be such a full, clear, 'and exact description of my invention as will enable those skilled the My invention relates to a pavement the wearing surface of which has in itself inherent stability; forexam le,such a wear-' ing surface as is describe in U. S. Letters Patent No. 727,505.- This pavement comprises in addition to the wearin'gjsurfacea ou-ndationand a la er ofgcoarse broken stones or other materlals so laid as to penetratesomewhat into the foundation whereby" they are old firmly in. place, the projecting portion .t ereof projecting into the topping or wearing surface, which, being in its nature firm and stable, unites to form a pavement of great wearing possibilities.

Myinvention will be understood by refer- Figure 1, re resents asimilar view of a pavement ,em .odyin my invention, the wearing surface not lieing shown. Fig. ,2, represents a similar view of my completed pavement.

' My improved meansfor preventing rela- .tive movement of the topping and foundation. differs in principle from any of the expedients knownto the art. [I do not rely upon the adh'esiveness of any compositlon forming a layer intermediate of the to ping and the foundation, such as the cus' Ion coat hereinbefore. mentioned. Neither do I rely u on 'thecombined adhesivenessand immoblity of an intermediate layer, as for instance, the b inder'course. In my pavement there' iano necessity for-an intermediate-layerg-g 'e'sole function .of which. is; to prevent cree ,ingbetween foundation- 'and topping. "In ieu of such alayer I; use coarse broken stone .or other material, so

of such -'inaterial-penetrates and is. fined in j the concrete3or-other foundation, while the upper portions of such elements mterlock' elements this act as numberless dowel pins, securely locking together, and preventing the slightest displacement of the adjacent surfaces. v

In Fig. 1., which'represents my invention, the Intermediate layer is seen to be omitted,

and in its place is found the broken stone 6,

one ortion, 7 of which is securely held by.

the oundation, whilethe other portion, 8, interlocks with the topping. In constructing my pavement theingredients jcom osing the hydraulic concrete or other foun ation, 4, are thoroughly-"mixed,

and well tamped whilewet or soft so as to be compaot, and so as" to have the voids in the mineral aggregate filled with thefmortar or binding'element. Then while the foundation 1 is still plastic, the coarse stone or other material 1s "scattered over its surface, and gently tamped so as. to partially pone trate the same. The subsequent setting or.

hardening of the concrete or other foundation will cause the stone to .be so securely held iinplace'as to be substantially 'an inte- 4 grid part, of such foundation, and the foun dation so treated will present an extremely rough surface. Upon this rough surface the topping is laid in any desired manner, and by its interlocking with -the protruding stone, is'preventednfrom creepin or from being displaced, no matter how eavy the traffic.

While I have described my I invention chiefly in connection with a hydraulic concrete foundation, it is obvious that the in venti'on itself isfindependent of the nature of'the particular, foundation or course u on which the topping is to lie-supported], t is merely necessary that the stone be tamped into such su porting course while the course is yet flexib e-or before it has set or hardened. .Of course in re airing old pavements whereinflthe'foun ation has already become hardened, it is necessary to soften the foundation to some extent before tampin" in the'stoiie or other material.

avin'" described my invention, what I an defiireto secure by Letters Patent seu imtprovedpavement consisting of a suitable oundation, coarse broken stone or other material tamped-into such foundation and partially protruding therefrom, and .a

bituminous ;wearing= fsurfe'ce' interlockin being rolled in lace u on said foundation with the protruding endso'f such materia when said foun ation as become dry and such wearing surface bein composed; of hard. v mineral ingredients of severe grades so pro- WALTER BURGESS WARREN. fiortioned to eachother as to possess" an in- In presence -of-' erent stability and a. bituminous cement J E. R. HAYES, or hinder said bituminous wearing surface SAUL SIPPERSTEIN. 

